Camera-based surveillance systems represent the latest in video technology, used in many environments, such as along streets, and in airports and business establishments. Today's images are much better than in the past, when shots were blurry and hard-to-follow. The latest setups feature live streaming video with sharp, color images at up to 500 lines of resolution. The systems allow police or other monitoring personnel to remotely monitor and control the cameras, zooming in on trouble spots from headquarters miles away.
Digital surveillance systems are growing more powerful, less expensive—and increasingly common. As an example of one application, many U.S. cities are using traffic cameras to photograph motorists who drive through red lights.
The latest technology lets operators pan, tilt or zoom their cameras via the Internet or a company's computer network. A single monitor can simultaneously display images from a number of cameras, reducing the expense of multiple screens. Finding a particular image used to mean hours of scrolling through analog tapes. Doing it digitally takes less than a minute. The systems can now trip an alarm or send alerts by page, e-mail or telephone.
Video surveillance systems today generally rely on operator visual monitoring for detection of incidents. The limited automation commonly available includes timed video multiplexing and alarm-based video switching. The amount of video data presented to security personnel for monitoring can be overwhelming; resulting in reduced vigilance, late detection, or event detection failure. Computer automated image analysis can provide automated event detection and alarm generation operations, thereby reducing the volume of data presented to security personnel. Computer automated surveillance can monitor large areas and handle complex time-varying images. Presentation of a video feed to surveillance personnel after computer image analysis has detected an event will support improved vigilance and increase the probability of incident detection.
Current video motion detection systems implement simplistic image processing approaches. False triggers are generated by moving foliage, passing headlights, cloud shadows, etc. Operation of these systems is only feasible in highly constrained applications.